Turanose is a reducing disaccharide naturally present in honey and its sweetness power is about half that of sucrose. It is an analog of sucrose, and has a chemical structure of 3-O-α-D-glucopyranosyl-D-fructose.
Because turanose is not fermented by a microorganism that causes dental caries, the turanose can be used as a calorie-free sweetener. Accordingly, turanose can play an important role in food, cosmetic, and pharmaceutic industries.
Japanese publications, patent No. 1993-252974 and J. Appl. Glycosci., 51, 223-227, are the only references that disclose an enzymatic process for producing turanose by treating an aqueous solution containing an amylaceous substance and fructose with cyclomaltodextrin glucanotransferase. In fact, the enzymatic process includes two important steps: transglycosylation of the amylaceous substances to fructose by cyclomaltodextrin glucanotransferase and hydrolyzation of the α-1,4-glucan chains of the transfer products by glucoamylase.
However, a method of easily producing high-purity and high-yield turanose has not been developed. Accordingly, it is very important to develop such a method of producing turanose so as to produce a calorie-free sweetener for use in foods, and additives for use in cosmetic products or medical products.